Chazal say that to make peace between man and wife is so sacred that we may transgress the very severe aveirah of erasing Hashem's name [with the Sotah water] in order to achieve it. With that backdrop we can understand this literally unbelievable story.
This is probably unprecedented in rabbinic history.
But it worked and zchus hatzadikim yaazor vi-yagein vi-yoshia!!!